The present invention relates to multilayered films with low temperature impact resistance comprising a first and a second layer, wherein the second layer contains polycarbonate, and wherein the first layer is an impact-modified polyalkyl acrylate which has a layer thickness of less than 25 μm. The invention moreover relates to the production of these multilayered films, such as e.g. mobile phone lenses, which contain the multilayered shaped articles mentioned.
The prior art on multilayered films is summarized in the following by way of example.
PC/PMMA films which pass a falling ball test without fracture at room temperature with a ball weighing 13.5 g are already described in WO 2008/074525. This application gives no indication of the behaviour of such composite films at −30° C. WO 2008/074525 describes multilayered articles of plastic with a base layer of polycarbonate and a poly(meth)acrylate layer attached on this, wherein the total thickness of the multilayered article of plastic is between 0.05 mm to 0.49 mm and between 1.21 mm to 5 mm and the total thickness of the poly(meth)acrylate layer is between 5% and 50% of the total thickness of the multilayered article of plastic, and the two layers are bonded by coextrusion. The films described here have a layer thickness which lies outside.
JP 2006-103169 A describes a multilayered product with an acrylic resin layer of from 50 to 120 μm and a polycarbonate layer of from 0.5 mm to 1.2 mm (500 μm to 1,200 μm), which therefore lies outside the range claimed here.
It has been found, however, that the known acrylate/polycarbonate films have a still inadequate low temperature impact resistance for some uses, in particular for external uses with permanently high requirements with respect to the impact resistance, such as, for example, glazing.